-LRB- CNN -RRB- -- Two airplanes came too close to one another while attempting to land at a Detroit airport , a federal official said early Saturday , days after another close incident involving three jets at a Washington , D.C. airport .

A Delta flight from Phoenix was coming in to land Friday night at the Detroit Metro Airport as a small regional jet was trying to land , said Elizabeth Cory , a spokeswoman for the Federal Aviation Administration .

The two planes were separated by approximately two horizontal miles . Standard separation distance is three miles , Cory said , noting that an investigation is under way .

CNN first learned of the incident from an alleged passenger who said he could see a regional jet below them from his cabin window .

`` Air traffic control was aware that they had a situation where separation was less than they would like , '' Cory said .

Both pilots had visual contact with each other and neither plane was at risk of colliding with the other , she added .

Friday 's incident in Detroit comes a day after federal authorities acknowledged that three U.S. Airways-operated jets at Reagan National Airport came closer than they should have because of an air traffic control `` miscommunication . ''

Feds investigate 3 planes flying too close at DC-area airport

The incident occurred Tuesday afternoon when air traffic controllers were making adjustments for landing and departing aircraft because of bad weather .

The Chautauqua Airlines flight came within 800 vertical feet and .82 nautical miles after takeoff of an arriving aircraft , identified as a Republic Airlines flight , authorities said .

The third plane involved was another Republic Airlines flight , which was taking off and came within 2.07 nautical miles and 800 vertical feet of the arriving flight .

`` During the switchover of operations , miscommunication between the Tracon and the DCA tower led to a loss of the required separation between two regional jets departing from Runway 1 and a regional jet inbound for Runway 19 , '' the Federal Aviation Administration said .

`` Tracon , '' or terminal radar approach control , is a reference to a regional radar facility . `` DCA '' is the International Air Transport Association code for Reagan National Airport .

`` At no point were the three aircraft on a head-to-head course , '' said Transportation Secretary Ray LaHood .

The FAA is investigating and plans to take `` appropriate action to address the miscommunication '' of Tuesday 's incident .

`` Such near misses and any operational errors are calls to action , '' Rep. John L. Mica , R-Florida , said after the Tuesday incident . `` I 'm asking our Aviation Subcommittee staff and FAA to thoroughly review what happened . ''

Last year , an air traffic controller was suspended for failing to respond to two planes heading into National Airport after he fell asleep on the midnight shift .

The two planes landed without incident .

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FAA spokeswoman : A Delta flight from Phoenix was coming in to land Friday night

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A small regional jet was also attempting to land at the time , she says

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They were separated by two horizontal miles

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The standard separation distance is three miles